(a) Field of the Invention
The present invention relates to a hydraulic pivot device capable of imparting controlled arcuate displacement to a support housing or cage secured to a boom which is normally attached to a vehicle whereby the support housing or cage may be arcuately displaced on a pivot by applying fluid pressure to a piston controlling the axial rotation of the pivot and wherein the piston is positively interlocked to a desired position.
(b) Description of Prior Art
It is known to pivotally connect a support housing or cage to a hydraulic boom whereby the cage can be arcuately displaced on a connector element which is secured to the boom or an intermediate boom element. Such devices utilize various types of gearing arrangements which are operated by various means such as, for example, a crank arm which is manually rotated whereby the cage is caused to pivot along a horizontal plane in the right or left direction depending on the direction of rotation of the crank lever, i.e. either to the right or to the left. A disadvantage of this type of device is that it is bulky, requires frequent maintenance and repair, and are difficult to operate by the operator. Because of their construction, they are also hazardous as the crank arm protrudes from the housing and may be the cause of serious accidents, particularly when the support cage is located close to electrical transmission lines.